The present disclosure relates to a heat-pump system.
A heat-pump system is a system that includes a heat pump cycle capable of performing a cooling or heating operation. The heat pump system may be linked to a hot water supply device or a cooling/heating device. That is, it is possible to produce hot water by using a heat source obtained through a heat exchange between refrigerant for the heat pump cycle and a certain heat storage medium or perform air conditioning for cooling and heating.
The heat pump cycle includes a compressor for compressing refrigerant, a condenser for condensing refrigerant compressed by the compressor, an expansion device for decompressing refrigerant condensed by the condenser and an evaporator for evaporating decompressed refrigerant.
The heat-pump system may be an electrical heat-pump system or a gas heat-pump system.
A compressor having a relatively small or intermediate capacity operates in the electrical heat-pump system and the compressor may operate with an electric motor.
On the contrary, the gas heat-pump system needs a compressor having a large capacity for an industrial facility or for conditioning air in a large building, rather than for a typical home. That is, in order to operate a compressor for compressing a lot of refrigerant to a gas having a high temperature and a high pressure, the gas heat-pump system may be used as a system that uses a gas engine instead of the electric motor.
The gas heat-pump system includes an engine that uses a mixture (hereinafter, referred to as “mixed fuel”) of fuel and air to generate power. As an example, the engine may include a cylinder to which the mixed fuel is supplied and a piston that is provided to be capable of moving in the cylinder.
According to such a typical heat-pump system, since oil is not easily separated from refrigerant circulating during the heat pump cycle, there is a limitation in that the compressor lacks oil.